early pregnancy ultrasonographic evaluation
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Early Pregnancy Ultrasound
Presented byPresented by
Dr/ Ahmed Walid AnwarDr/ Ahmed Walid AnwarAssistant professor of Obs & Gyn Assistant professor of Obs & Gyn
Benha Faculty of MedicineBenha Faculty of Medicine
EgyptEgypt20142014
OBJECTIVES
Ultrasonographic evaluation of early
pregnancy and its complications
Early Pregnancy Ultrasound report
NORMAL
ABNORMAL
Location Structure Viability Dating Number
•Assessment of other pelvic masses ????
•Screening for fetal abnormalities ????
•Assisting CVS and amniocentesis????
Structure & Viability
Structures of 1st Trimester Pregnancy
Gestational sac
Yolk sac
Embryo/fetus
Presence of cardiac activity
Gestational sacVisible at 4-5wks GA with
TVUS & at 6 wks GA with TAUS.
Eccentric echogenic ring with anechoic center .
Measure by Mean Sac Diameter.
GS size increases by about 1mm/day in early pregnancy
Discriminatory zone: serum hCG level in which GS is expected to be visible by US : hCG >2000 mIU/ml by TVUS& hCG >6000 mIU/ml by TAUS
Structures of 1st Trimester Pregnancy
Yolk sac: : bright ring with anechoic center located inside GS
seen at 5wk GA & persists to 11-12 weeks. Embryo/fetus: seen by TVUS as thickening of yolk at 6wks GA.
Presence of cardiac activity: usually seen around the time fetal pole is present, further confirming viability (6th wks)
Yolk sac
Fetal pole
Confirming intrauterine gestation
Confirming intrauterine gestation
1) Double decidual sac sign
3) Double bleb sign2) Intradecidual sign
Dating
04/13/2312
Early dating of Early dating of pregnancypregnancy
5 – 9 weeks : use of mean GS diameter
6 – 12 weeks : use of CRL (most accurate
dating of early pregnancy)
After 12 weeks : use of BPD
5 – 9 weeks : use of mean GS diameter
6 – 12 weeks : use of CRL (most accurate
dating of early pregnancy)
After 12 weeks : use of BPD
Formulas to Calculate gestational age
MGSD (mm) + 30
= gestational age
(days) (between 5
and 9 weeks)
CRL (mm) + 42 =
gestational age
(days) (between 6
and 12weeks)
Diagnosis of multiple Diagnosis of multiple pregnancypregnancy
Types of multiple pregnancyTypes of multiple pregnancy
Twin peak (or Lambda sign) pathognomonic for dichorionic placentation
T-sign pathognomonic for monochorionic placentation
Other roles of US Confirm fetal number . Confirm viability. Diagnosis of vanishing twin syndrome. Exclude any malformation or conjoined twins
(especially at age > 35y = genetic amniocentesis)
Needed with other procedures CVS fetal reduction
Abnormal early (first trimester) pregnancy
Abnormal early (first trimester) pregnancy
Failed early pregnancy.Failed early pregnancy.
Pregnancy of uncertain viability (i.e. IU pregnancy in a situation with no
enough criteria (usually on ultrasound grounds) to confidently categorize a pregnancy
as a miscarriage).
Pregnancy of unknown location.
Ectopic pregnancy
Trophoblastic disease
Subchrionic hemorrhage
Incomplete abortion (retained products of conception)
Failed early pregnancyFailed early pregnancy
& &
Pregnancy of uncertain viability
Failed early pregnancy
(FEP(
Pregnancy of uncertain viability
(PUV(
No No cardiaccardiac activity activity with with CRLCRL
≥≥77mmmm < 6mm
No fetal pole with MSD
> 25 mm (Anembryonic
Pregnancy)
< 20mm
Others Absence or inadequate growth on serial scans at least 7-10 days
Mean GSD < 25mm and containing yolk sac only
Management Termination Follow up US in 7-14 days with serial beta HCG correlation…viable or nonviable.
TVUS criteria of :Doubilet et al., N Engl J Med. 2013 Oct 10;369(15):1443-51
US poor prognostic indicators of pregnancy include:
No yolk sac, where:MSD > 8 mm embryo seen
Irregular gestational sac Low position of the gestational sac
Doubilet et al., N Engl J Med. 2013 Oct 10;369(15):1443-51
Anembryonic Pregnancy
Pregnancy of unknown location
Pregnancy of unknown location (PUL)
PUL = +ve pregnancy test + no IU or Ext.U pregnancy in US scan
↓↓↓↓↓Differential diagnosis is:
1. very early pregnancy, not detected with ultrasound
2. complete miscarriage
3. unidentified ectopic pregnancy
Ectopic Pregnancy
True vs. pseudo-gestational sac
True GS (DDSS)
Fluid collection (or sac) shows a small “beak sign” that connects with or points toward the uterine cavity line
HETEROTOPIC PREGNANCY
Yolk sac Fetal pole
Other types of ectopic pregnancy
Cervical ectopic pregnancy
GS within the cervix . Abnormally low sac position. Colour Doppler : hypervascular trophoblastic
ring in the cervical region .
Interstitial ectopic pregnancy
Eccentric gestational sac: the diagnosis is suggested by
visualisation of an intrauterine gestational sac or
decidual reaction located high in the fundus, that is
surrounded by less than 5 mm of myometrium in all
planes.
Interstitial line sign : an echogenic line from the mass
to the endometrial echo .
Sonographic features of Caesarean scar ectopic pregnancy (CSEP)
empty uterus
empty cervical canal
GS in the anterior part of
the lower uterine segment
absence of myometrium
between the bladder wall
and the GS
Molar Pregnancy
Molar pregnancy ( Snow storm+ Theca-lutein cysts )
Subchorionic Hemorrhage
Retained products of conception (incomplete abortion)
Thickened Nuchal Tanslucency (NT): Used for screening (SS) for Down’s syndrome in first trimester
Serial screening: Pregnancy associated plasma protein levels, hCG levels, NT thickness
Measured during 11-14 wks gestational age Seen on sagittal image as increased subcutaneous non-septated fluid in posterior
fetal neck Measurement >3mm usually considered abnormal, however exact cut off
measurements are dependent on maternal age/gestational age Detection rate of screening for Down’s Syndrome in first trimester:
sequential screening with NT: 82-87% NT alone: 64-70%
Safety of ultrasound in pregnancy
General perception is that ultrasound is safe (It is not
ionising radiation)
However, bioeffects can be either thermal or mechanical
(i.e. cavitations) with high power ultrasound
One RCT of repeated routine ultrasound with Dopplers in
the 3rd trimester found a small but significant decrease in
birth weight in the exposed cohort
A meta analysis showed males exposed to ultrasound in
uterus are more likely to be left-handed
How to reduce biohazards
ALARAAs Low As Reasonably Achievable
ALARA principle: Lowest acoustic power Shortest duration Least exposure to sensitive target tissues
Take home message
Ultrasound is no substitute for a good history
ALWAYS do an abdominal scan with ( Full bladder)
before using the vaginal probe with ( Empty bladder)
You will always be better than sonographers because
you know the anatomy and pathology
Avoid premature conclusions
Take home message Systematic scan should be performed
US scans are useful to be combined with HCG tests
before decision.
With ultrasound , an early intervention or
conservative management in pregnancy can be
determined.
General perception is that ultrasound scan is safe in
pregnancy.
E.mail:::ahwalid2004@yahoo.com
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